1. Field of the Invention
The present general inventive concept relates to an image-forming device, and more particularly, to a device and method to efficiently store data in an external memory.
2. Description of the Related Art
Portable data storage devices (hereinafter, referred to as external memories) include magnetic discs or CD-ROMs, Universal Serial Bus (USB) discs, and the like.
Since more problems such as bottlenecking are caused on computer interfaces as multimedia functions are becoming in more demand on computer systems, more attention is drawn to the use of the USB discs.
Such USB discs are manufactured as interfaces for solving low transmission rates of existing external extension ports (Serial, Parallel), which are serial ports that cause inconvenience to a user due to limited numbers of connections for peripherals.
Compared to the external extension ports used for connecting peripherals (such as modems, printers, scanners, and the like), the USB discs have an advantage in that the USB discs are capable of connecting all basic peripherals (such as a keyboard, monitor, mouse, printer, modem, and the like), which must be connected in different modes when using the external extension ports. Further, when new peripherals are plugged into a computer, the USB disc automatically recognizes the new plugged-in peripherals, allows 127 peripherals to be connected at maximum with automatic recognitions rather than a rebooting or a setup process, and uses a voltage of 5V with a data transmission rate of 12 Mbps at maximum. The USB disc can be easily installed with its full PnP mode supports, and does not need extra peripherals since most mainboard chipsets contain a USB controller. Recently-manufactured mainboards include a USB chipset and terminals so the USB-related peripherals can be more conveniently used.
The USB disc is equipped with a flash memory unit therein so that users can store data files, voice files, audio files, compressed video files, and the like, in real time, for which a Scan2USB function has been introduced.
The Scan2USB function refers to a function enabling scanned images from a digital photocopier or an image-forming apparatus having a scanner to be stored in a USB memory directly connected thereto (i.e., without a connected personal computer). Therefore, users can exert less effort with a personal computer to scan and store images or documents into the USB memory.
However, the USB memory has limitations due to characteristics of storage media since the USB memory is also a piece of the storage media. Conventionally, if a user sends a job instruction for the Scan2USB function, data is stored in the USB memory. However, if the USB memory indicates that it is full, a problem occurs in that the ongoing job is terminated.
That is, even though the user checks the USB memory status in advance and determines that a memory size is sufficient so as not to interrupt a storing job due to a lack of memory, and then performs the Scan2USB function, the ongoing job may still be terminated if the memory indicates that it is full when the memory size is substantially smaller than the user has judged. Thus, the user has to secure more memory to make up for the insufficient memory size, and then have the job performed. In other words, the user has to check the memory size and judge whether the current job can be performed before carrying out the job. However, the user has to secure the memory size based on the user's subjective judgment since there is no objective data about how much memory scanned files take up, which causes the above problem.